Physical Activity Promotion in Breast Cancer Survivors

Approximately 300 breast cancer survivors living in Northern Alberta will be randomized to one of four groups: (1) an exercise recommendation only group (viewed as the current standard of care), (2) an exercise recommendation plus pedometer group, (3) an exercise recommendation plus printed materials group, and (4) an exercise recommendation plus pedometer and printed materials group. Our primary hypothesis is that participants in the three intervention groups will report a greater positive change in physical activity than participants in the exercise recommendation only group. Furthermore, we expect that participants receiving the combined pedometer and printed materials intervention will report the greatest change in physical activity. Our secondary hypotheses are that these interventions will also result in improved QoL and more positive social cognitive beliefs about exercise in breast cancer survivors. Our sample size was determined by a power calculation. Based on the literature, we believe that an increase of 2,000 steps per day is a meaningful change that will result in health benefits for breast cancer survivors. We estimate a standard deviation of about 4,000 steps per day. Therefore, to detect a medium standardized effect (d = .50) with a power of .80 and a two-tailed alpha <.05, we need 63 participants per group. To account for a possible 15% loss to follow up, we will randomize 75 participants to each group. Our printed materials will be developed based on the tenets of the theory of planned behavior and will include activities designed to enhance instrumental and affective attitudes, injunctive and descriptive norms, and self-efficacy and perceptions of control. These materials will be developed based on our previous research identifying the key beliefs that should be targeted in a theory of planned behavior-based intervention.

Our procedure will be to identify and screen potential participants for eligibility through the Alberta Cancer Registry. After obtaining written informed consent from the individual's treating oncologist, all eligible participants will be sent a letter of invitation to participate in the study. Interested participants will complete a baseline questionnaire that will include measures of physical activity (the Godin Leisure-Time Exercise Questionnaire), QoL (Functional Assessment of Cancer Therapy-Breast and Anemia), and social cognitive variables from the theory of planned behavior (based on the guidelines from Ajzen and our previous research). Participants will also wear a pedometer for a 7-day monitoring period to obtain baseline steps. Participants will then be randomized to one of four groups. Depending on randomization, the participants will then receive the appropriate materials. All groups will be recommended to accumulate at least 30 minutes of moderate intensity physical activity at least five days per week which would result in about 15,000 steps per week (or 2,000 steps per day). At the end of the 12-week intervention period, all participants will complete the same post intervention questionnaire and undergo another 7-day monitoring period to obtain step values. Participants will be contacted at 6 months for follow-up and complete the same questionnaire for a final time.